GM Service Manual Online
For 1990-2009 cars only

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Action

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Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn ON the headlamps.
  2. Ensure that the headlamp dimmer switch in is the HIGH position.

Do the high beams illuminate?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Is only one lamp operative?

Go to Step 8

Go to Step 4

4

  1. Place the headlamp switch in the HDLP position.
  2. Disconnect connector C209.
  3. Install a fused jumper between the headlamp battery positive voltage supply circuit and the switched high beam voltage supply circuit.

Do the high beams illuminate?

Go to Step 5

Go to Step 6

5

Inspect the harness connection of the multifunction turn signal lever for a poor connection. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

6

Test for a open, poor connection or a short to ground in the high beam headlamp supply voltage circuit between the multifunction turn signal lever and the underhood fuse block. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 7

7

Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

Did you complete the repair?

Go to Step 10

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8

Repair the short to ground, open, or high resistance in the inoperative headlamp power supply or the ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

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9

Replace the multifunction turn signal lever. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the repair?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the situation?

System OK

Go to Step 3